This application relates to an ink jet cartridge or cassette as used in an ink jet printer, and more particularly to an apparatus and method for reducing the introduction of air into the system. It will be appreciated, however, that the invention may find application in related environments and applications that encounter these same issues.
It is generally known in the art to form a cartridge housing or body from a plastic material. The housing includes one or more cavities or chambers that hold a predetermined supply of ink. For example, a single color of ink may be provided in a single chamber cartridge or multiple chambers may be provided, for example, each holding a different color ink stored therein for selective use in a color printer. It is also generally known to provide an ink absorbing member such as a reticulated polyethylene or melamine foam that fits within the chamber(s). In some arrangements, the ink absorbing member fills the substantial entirety of the chamber, while in other instances a portion of the ink supply is free ink and the remainder is stored in the ink absorbing member. One or more outlet ports communicate with the respective one or more chambers through outlet passages. The outlet passage proceeds through a first or bottom wall of the housing. A supply needle from an associated printer extends through the outlet port and thus conveys ink from the housing to a recording head or printhead.
Print quality can be adversely effected by the introduction of air into the ink chamber, outlet passage, or outlet port. Thus, manufacturers of ink cartridges are careful in the design and assembly, i.e., filling, to limit the potential for air introduction into the system. One area of potential air introduction is between the chamber and outlet passage. It is common to employ a filter or screen, such as a woven plastic mesh filter, between the ink absorbing member and the outlet passage. The screen prevents contaminants from reaching the printhead from the ink jet cartridge and also aids in maintaining capillary flow from the chamber to the printhead. During assembly, any wrinkles or mis-positioning of the screen can result in print quality problems such as voids or ink starvation. Thus, a need exists to improve print quality and particularly limit the potential for air bypassing the screen as ink proceeds from the housing chamber to the outlet port.